Electron and hole mobility of rutile GeO2 from first principles: An ultrawide-bandgap semiconductor for power electronics

Rutile germanium dioxide (r-GeO2) is a recently predicted ultrawide-bandgap semiconductor with potential applications in high-power electronic devices, for which the carrier mobility is an important material parameter that controls the device efficiency. We apply first-principles calculations based on density functional and density functional perturbation theory to investigate carrier-phonon coupling in r-GeO2 and predict its phonon-limited electron and hole mobilities as a function of temperature and crystallographic orientation. The calculated carrier mobilities at 300 K are μelec,⊥c→=244 cm2 V−1 s−1, μelec,∥c→=377 cm2 V−1 s−1, μhole,⊥c→=27 cm2 V−1 s−1, and μhole,∥c→=29 cm2 V−1 s−1. At room temperature, carrier scattering is dominated by the low-frequency polar-optical phonon modes. The predicted Baliga figure of merit of n-type r-GeO2 surpasses several incumbent semiconductors such as Si, SiC, GaN, and β-Ga2O3, demonstrating its superior performance in high-power electronic devices.